Mining machine having an auxiliary cutter



J. R. SIBLEY 3,362,753

MINING MACHINE HAVING AN AUXILIARY CUTTER Jan. 9, 1968 4 Sheets-Sheet 1 Filed Feb. 1, 1965 Fig.2.

Fig. I.

INVENTOR JOHN R. SIBLEY his ATTORNEY J. R. SIBLEY 3,362,753

MINING'MACHINE HAVING AN AUXILIARY CUTTER Jan. 9, 1968 '4 Sheets-Sheet 2 Filed Feb. 1, 1965 INVENTOR. JOHN R. SIBLEY his ATTORNEY mm 0: 5 mm 0 J. R. SIBLEY Jan. 9, 1968 MINING MACHINE HAVING AN AUXILIARY CUTTER 4 Sheets-Sheet a Filed Feb. 1, 1965 Now Jlll JL INVENTOR.

JOHN R. SIBLEY [M U-W mum his ATTORNEY United States Patent C M 3,362,753 MINING MACHINE HAVING AN AUXILIARY CUTTER John R. Sibley, Franklin, Pa., assignor to Joy Manufacturing Company, Pittsburgh, Pa., a corporation of Pennsylvania Filed Feb. 1, 1965, Ser. No. 429,589 13 Claims. (Cl. 299-59) This invention relates to mining apparatus and more particularly to a new and improved means for forming a roof in an underground passageway and for removing cusps formed by a separate primary cutting means.

In a continuous mining apparatus of a known type, a plurality of laterally adjacent rotatable boring elements are employed to form a pattern of overlapping contiguous bores in a mineral vein. As a result of such overlapping bores, portions of mineral, commonly called cusps, remain outwardly adjacent the intersection of such bores. The more efficient of the prior known devices employed a roof trimming cutter of the drum type for removing such cusps and for removing a portion of the mineral thereabove to provide a well-formed clearance passageway.

Although such prior known devices have served the purpose for which they were designed, they have not been entirely satisfactory under all conditions of operation due to their inability to provide suflicient clearance for the combined drive housing and support elements of the drum. The problem of adequately supporting and driving bitted cutter drums has seriously limited their effective application.

The general purpose of this invention is to overcome the above disadvantages by providing a cutter drum having the drive means encased within the drum and a cutter drum support means which is compact, simple in construction, and serves only as a structural and torque anchor means.

It is, therefore, an object of this invention to provide a new and improved roof and cusp cutting means.

It is another object of the present invention to provide a new and improved roof and cusp cutting means of the drum type having novel drive means located within the drum.

It is a further object of the present invention to provide a new and improved roof and cusp cutting means of the drum type having novel support means which serve only as a structural and torque anchor means.

It is still another object of the present invention to provide a new and improved roof and cusp cutting means of the drum type having novel drive means located within the drum and a pair of cone cutters disposed at the ends of said drum to provide a greater range of vertical adjustment, an improved roof contour, and to reclaim an increased volume of material.

These and other objects of the invention will become more apparent upon consideration of the following detailed description thereof when taken in conjunction with the following drawings, in which:

FIG. 1 is a partial side elevational view of the mining apparatus constructed in accordance with the principles of this invention;

FIG. 2 is a front elevational view of the mining apparatus of FIG. 1, showing the arrangement of the boring arms and their cutting orbits in dot and dash outline with parts of the outboard boring heads broken away to show the support structure for the top drum cutter;

FIG. 3 is an enlarged fragmentary section taken through one half of the cutter drum on line 33 of FIG. 2, illustrating the drive for the cutter drum;

FIGS. 4A and 4B, taken together, constitute an enlarged fragmentary horizontal section taken through the 3,362,753 Patented Jan. 9, 1968 cutter drum generally on line B-B of FIG. 5 and illustrating a second embodiment of the apparatus of this invention of this invention; and

FIG. 5 is a diagrammatic view illustrating the cutting orbits of the primary cutters and the top drum cone cutter in its lowermost and uppermost positions.

Referring to FIG. 1 of the drawings, it will be noted that a mining apparatus constructed in accordance with the principles of this invention comprises a suitable, elongated frame generally designated 12 having conventional endless tread means (not shown), well known in the art, and power means for said tread means for propelling the apparatus along the ground. Mounted adjacent the forward end of frame 12 is an elongated main transmission 14 which has suitable output means for rotatively driving a plurality of boring heads generally designated 16, only one of which is shown in FIG. 1. Although preferably four such heads are employed in the instant device, it should be appreciated that the principles of this invention contemplate the use of any suitable number of boring heads. Suitable drive means, such as a pair of electrical motors (not shown) are suitably operatively connected to drive the transmission 14 in a manner well known in the art.

The forward surface of the transmission 14 has laterally spaced hubs 18 suitably, rigidly, secured thereto, which hubs have suitable gear trains and output shafts (not shown) for rotatively driving the boring heads 16, respectively.

Rotary boring heads 16 are driven in a predetermined time relationship so that interference between adjacent boring heads is obviated, as is well known in the art. Boring heads 16 have central hub portions 20, which are rigidly, coaxially, secured to the driving shafts therefor, respectively, and which hub portions 20 have central forwardly projecting pilot cutters 22, respectively.

These heads 16 may assume various forms but for illustrative purposes, as herein preferably shown, comprise opposed radial boring arms 24 extending from the hub portions 20, said arms carrying outer cutter supports or bit carriers 26 and an intermediate cutter support or bit carrier 28. Each of the cutter supports has suitable cutter bits 30 secured thereto to remove mineral from a vein in a manner well known in the mining art. The two inboard rotary boring heads may have only one arm, if desired (see FIG. 2), rather than opposed arms as illustrated on the outboard boring heads. As such primary cutting means are conventional and have been widely used by applicants assignee, no further illustration or amplifica tion is believed necessary.

Conventional conveying means, generally indicated at 29, extending longitudinally cent-rally of the frame 12, extend forwardly and downwardly to the rear of the lower portions of the boring heads for receiving and conveying disintegrated mineral rearwardly of the apparatus to a convenient point of delivery in a manner well known in the mining art.

With the heretofore described structure, it will be realized that four circular cross sectional bores are formed by four boring heads in a mineral vein as shown in dot and dash outline in FIG. 2. The axes of rotation of the heads 16 are on the same horizontal plane so that a cusp is formed between each of the adjacent bore openings above and below a horizontal plane extending centrally therethrough. Thus, with four boring heads, three upstanding cusps remain which extend upwardly from the surface over which the mining apparatus travels and three cusps remain which depend from the upper surface of the mineral vein.

The lower cusps are removed by means of plows, generally indicated at 32, which are rigidly secured to the lower edge of frame 12 and are longitudinally aligned with the upstanding cusps. Flows 32 comprise a plurality of downwardly and forwardly extending Wedge-shaped elements 34 which remove the upstanding cusps in a simpler and more compact structure than any active cutting device and cause the upstanding cusps to break down in large fragments.

An upper trimming cutter means or elongated, cylindrical, roof cutter drum, generally designated 36, having cutter bits 37 circumferentially, suitably mounted on the outer surface thereof, is provided for removing the upper depending cusps and for cutting additional clearance in the roof of a mine passageway. A pair of cutter drum supports or arm members 38 are pivotably connected about laterally spaced, horizontally oriented, pivots 40, which are suitably secured rearwardly of the boring heads to the upper portion of the transmission 14. These supports extend upwardly and then inwardly toward each other and are rigidly secured within the cutter drum as will hereinafter be more fully explained.

Means are provided for swinging the arm members 33 about their respective pivots, said means comprising a pair of suitable extensible hydraulic jacks 42 having the head ends thereof suitably, pivotably mounted at 44 on brackets 46 secured to the upper rear portion of transmission 14 and having the rod ends thereof suitably pivota bly secured at 48 on lugs 50, which are secured to the drum support members 38. Thus, when liquid under pressure is properly supplied to the hydraulic cylinders 42, the support members 33 may be swung either upwardly or downwardly about their pivots to vary the elevation of the top drum cutter and by trapping liquid within the cylinders at the opposite sides of the pistons, the arm members carrying the cutter drum may be locked in adjusted position.

Reference is now made to the construction and arrangement of the horizontally disposed roof cutter 36, only one half of which is shown in detail in FIG. 3. Since the half illustrated is identical to the other half and symmetrical thereto about a plane passing through the line indicated at AA normal to the axis of the cutter drum, it is believed that a detailed description only of the portion shown will sufiice.

As shown in FIG. 3, the uppermost portion of support arm 38 extends into and rotatably supports cutter drum casing 52. on suitable bearings 53. A suitable seal 55 annularly seals the space between the support arm 38 and drum casing 52.. Support arm 38 is keyed at 54 to engage a torque reaction member 56 fixedly secured to a drive housing 58 within the cutter drum casing 52.

Suitably rigidly mounted within the drive housing 58 is a suitable electric motor as having a rotatable rotor 62 suitably rigidly secured to an elongated power shaft 64 which is coaxial with said rotor, such shaft being suitably, rotatably journaled in bearings 66 and 68. Electrical conductors (not shown) are disposed in the hollowed out portion of support arm 38 and member 56 and suitably electrically connect motor 69 to a suitable source of power. Rigidly secured onto the shaft 64 is a vane pump impeller having vanes or blades 70 for a purpose hereinafter more fully explained.

Secured to the left end reduced portion of shaft 64 by means of a keyed connection 73 and a cap screw 72 is a spur gear '74 which meshes with a plurality of planet gears 76 in turn meshing with an internal ring gear 78 which is rigidly secured to the drive housing 58. The planet gears '76 are journaled on shafts 86, respectively, supported by a rotatable planet carrier 82. Extending axially outwardly from the carrier 82 is a reduced portion 84 having a gear 86 mounted thereon which meshes with planet gears 88, which in turn mesh with an internal ring gear 99 rigidly secured to the drive housing 58. Planet gears 88 are journaled on shafts 92, respectively, which are supported or carried by rotatable planet carrier 94.

Extending axially outwardly from the carrier 94 is a reduced portion 96 keyed at $8 to engage a torque transmitting member or output shaft tilt), said output shaft being keyed at 102 to a radially inwardly extended portion 1434 of the cutter drum casing 52 and being suitably journaled within bearings 1G6 supported within the drive housing 58.

The entire drum unit, including the hollowed out portion of arms 33, is filled with a cooling medium, such as oil, by way of example. Leakage is prevented by annular seals 55 disposed between the drum and support arms 38. Rotation of the vanes or blades 70, which are integral with power shaft 64, effects circulation of the cooling medium in the general direction indicated by arrow 65, that is, leftwardly through the motor and gear train, through the ports 168, then to the right through the passage d fined by the drive housing 58 and drum casing 52, returning through the ports and 111, thus cooling the motorreducer package by the transfer of heat through the drum casing.

In operation, motor 60 rotates power shaft 64 in a given direction, which in turn effects rotation of the individual planet gears in the opposite direction. However, since the ring gear is fixed against rotation through drive housing 58 and keyed connection 54 to support arm 38, the planet carrier will revolve in the same direction as the power shaft. This rotational movement is repeated in the second stage gear reduction arrangement to effect rotation of the cutter drum in a direction identical to that of the power shaft. It will thus be seen that the motor 60 rotatively drives the cutter drum through the medium of a two-stage reduction gearing system at an angular speed substantially slower than the angular speed of rotation of the motor with all the elements of the drive packaged and contained by the drive housing 53 within the cutter drum. it is further apparent that by so containing the motor and reduction system in a separate rigid housing supported only at the torque reaction keyed connection 54 and the torque transmitting keyed connection 98, each with freedom to accommodate misalignment, the gear and motor elements are free of the effects of deflection and loads imposed on the cutter drum casing.

With reference to FIG. 2, it will be readily apparent that the top drum cutter is operative to remove the depending cusps left by the boring heads during their penetration through a mineral vein, said top drum cutter being adjustable to form a roof of a desired elevation.

As a result of this invention, an improved continuous mining apparatus is provided for dislodging and disintegrating the mineral of a solid mine vein in an improved and more efficient manner. By housing the drive for the top drum cutter within the drum, the supports are not compromised by the drive means and serve only as a structural and torque anchor means. This results in a simple, compact and rugged support which, at maximum extension, lies within the periphery or shadow S of the primary cut, thus utilizing a significant portion of the drum diameter to cut clearance above or beyond the separate primary cutting means.

A further advantage residing in the apparatus of this invention is the independence of the motor and drive units from the drum support to thereby minimize operating loads and deflections on said motor and drive units. Also, drive torque is provided without imposing bending or radial loads on either the drum or drive units. T lese and other advantages of this invention will be readily apparent to those skilled in the art.

FIGS. 4A, 4B illustrate another embodiment of the roof cutter of this invention comprising a generally horizontally extending top cutter frame generally designated 20% which is adapted to extend transversely across the upper portion of a conventional boring type mining machine. An upper trimming cutter means or elongated, cylindrical roof cutter drum, generally designated 201, having cutter bits 207, circumferentially, suitably mounted on the outer surface thereof, is provided for removing the upper depending cusps and for cutting additional clearance in the roof of a mine passageway. A portion 202 of the top cutter frame extends inwardly within a cutter drum casing 204 to which it is rotatably journaled by suitable bearings 203 and sealed by suitable seals 205. Portion 202 is also splined at 206 to engage a torque reaction member 208 which is fixedly secured to a drive housing 210 within the cutter drum casing 204.

Suitably rigidly mounted within the driving housing 210 is a suitable electric motor 212 having a rotor 214 suitably rigidly secured to an elongated tubular hollow power shaft 216 which is suitably rotatably journaled in bearings 218 and 220. Rigidly secured onto power shaft 216 is a vane pump impeller having vanes or blades 222 for circulating fluid within the sealed drum 201 through a similar path and passages (not shown) and for the same purpose as explained in connection with the embodiment first described.

Secured to the left end of power shaft 216 is a gear 224 meshing with a plurality of planet gears 226 in turn meshing with an internal ring gear 228 secured to tie drive housing 210. The planet gears 226 are journaled on shafts 230, respectively, which are supported by a rotatable planet carrier 232. Extending axially outwardly from the carrier 232 is a reduced portion 234 having an external gear 236 meshing with a second group of planet gears 238 in turn meshing with an internal ring gear 240 secured to the drive housing 210. Planet gears 238 are journaled on suitable shafts, respectively, supported by a rotatable planet carrier 242 in a manner similar to the arrangement described in connection with the first planetary gearing arrangement.

An internal spline 244 of reduced portion 234 engages a splined external portion 246 of an elongated internal transmission shaft 248 disposed within the bore of power shaft 216, the description and purpose of shaft 248 being hereinafter more fully explained.

Extending axially outwardly from planet carrier 242 is a reduced portion 250 having an external gear 252 meshing with a third group of planetary gears 252 which in turn mesh With an internal ring gear 256 secured to the drive housing 210. The planet gears 254 are journaled on suitable shafts 258, respectively, supported by rotatable planet carrier 260 having an axially and outwardly reduced portion 262, which is keyed or splined at 264 to a radially inwardly extending portion 266 of the cutter drum casing 204. Planet carrier 260 is suitably journaled within a bearing 268 supported within the drive housing 210. Thus, it will be seen that the cutter drum is driven through a three-stage reduction gearing arrangement at an angular speed substantially slower than the angular speed of rotation of the tubular power shaft 216.

For the purpose of providing a cut pattern which provides clearance to hide the support structure and which has other apparent and noted advantages, a pair of cone cutters generally designated 267 are provided. Said cone cutters are rotatably mounted on fixed spindles 275 rigidly secured at their bases to the top cutter frame 200 adjacent either end of the cutter drum. Each cutter 267 has a generally cone-shaped outer shell 269 with cutter bits 271 suitably mounted about the outer surface there of, said shell being suitably journaled by bearings 277 and 279 and sealed by suitable seals 281 to the fixed spindle 275. Cone cutters 267 are filled with a cooling medium, such as oil, for example, in order to transfer the heat generated by the gearing arrangement, herein after described, to the cone-shaped shell 269.

Transmission shaft 248 is suitably journaled in a bearing (not shown in FIG. 4A but illustrated as 270 in FIG. 4B for the shaft of the other half of the drum) located adjacent the end of the cutter drum and has secured thereto at its outer end a gear 272 which meshes with gear 274 secured to a shaft 276 suitably journaled within bearings 278 and 280. Each shaft 276 has a bevel gear 282 secured thereon which meshes with a similar bevel gear 284 suitably rigidly secured on a shaft 286 which is suitably journaled in bearings 288 and 290 supported within the cone cutter spindle 275. Secured to shaft 286 is a gear 294 which meshes with and drives internal gear 296 fixed within the cone cutter shell 269. Thus, the cones are rotated about their longitudinal axes at an angular speed slower than the angular speed of rotation of shaft 248.

Each cone cutter has its longitudinal axis oriented downwardly with respect to a horizontal plane passing through the line B--B (see FIG. 5) and laterally outwardly with respect to a vertical plane passing through the lines C-C. By angling the cone axes below horizontal, the cone cutters, when collapsed, lie within the periphery or shadow S of the primary cut to facilitate withdrawal of the mining apparatus within the mine entry or passageway. By angling the cone axes laterally outwardly from vertical, a shadow is formed behind the cone cutters to accommodate shrouding, support elements, adjusting means, and material handling means.

Any suitable extensible means, such as the hydraulic jacks described in connectionw ith the first embodiment, for example, may be provided for swinging top cutter frame 200 about horizontal pivots for the purpose of selectively varying the elevation of the drum and cone cutter assembly with respect to the primary cutting means. It should be noted, however, that any suitable arrangement of cutter support members, linkages, pivotal connections, etc., are contemplated within the scope of the present invention, such arrangement being dependent on the rib-to-roof contour desired. For example, reference may be had to copending application Ser. No. 429,588, filed Feb. 1, 1965, having a common assignee as the instant application, wherein is disclosed a pivotal cutter support construction which maintains the cone cutters in the same orientation relative to the drum cutter regardless of cutter elevation.

This embodiment has anadvantage over the embodiment first described in that additional production is obtained by adding width to the space mined and furthermore, such width provides a cut shadow behind the cone cutters to accommodate shrouding, support elements, adjusting means, and mate-rial handling means. By thus cutting clearance for the support and adjusting means, a greater range of vertical adjustment is possible to an amount slightly in excess of the cutter drum diameter. A further advantage residing in the use of the drum and cone cutter assembly of this invention is that the profile cut by such an assembly forms a desired arched rib-to-roof contour and also provides, with the cutter vertically retracted substantial lateral as well as vertical clearance. These and other advantages of this embodiment will be clearly apparent to those skilled in the art.

In both embodiments, the structure and operation of only one-half the drive and cutter have been described, it being understood that the other half is operative in the same manner and sychronously driven. However, because the loads on the drum are not always equally divided, the motor absorbing the smaller load will supplement the other in a manner well known in the art.

Preferred embodiments of this invention having been described and illustrated, it is to be realized that modifications thereof may be made without departing from the broad spirit and scope of this invention as defined in the appended claims.

What is claimed is:

1. A mining apparatus comprising: an elongated rotatable casing having cutting elements thereon; support means for rotatably supporting said casing; sealing means disposed between said casing and said support means for preventing leakage therebetween so that said casing is a fluid tight housing having a liquid cooling medium therein; drive means enclosed within said casing for rotating said casing; and means enclosed in said casing for circulating said cooling medium throughout said casing and said drive means.

2; A mining apparatus as specified in claim 1 wherein said support means are disposed at the ends of said casing.

33. A mining apparatus for removing mineral from a mineral vein comprising: a rotatable casing having cutter elements thereon; a drive housing enclosed within said casing; support means for rotatably supporting said casing; means connecting said drive housing to said support means with freedom to accommodate misalignment occurring during such use, for preventing rotation of said housing; a drive means enclosed within said casing for rotating said casing; said drive means comprising at least one motor secured to said housing and a gear reduction mechanism operatively connecting said motor to said casing with freedom to accommodate misalignment occurring during such use.

4. A mining apparatus comprising: a rotatable casing having cutting elements thereon; a drive housing enclosed within said casing; a support means for rotatably supporting said casing; means connecting said drive housing to said support means with freedom to accommodate mis alignment occurring during such use for preventing rotation of said housing; a drive means enclosed within said casing; said drive means comprising at least one motor secured to said housing and having a rotatable shaft, a multi-stage gear reduction mechanism operatively connected to said shaft, and means connected to said gear reduction mechanism with freedom to accommodate misalignment du-ring such use for transmitting torsion from said gear reduction mechanism to said rotatable casing; means secured to said rotatable shaft for circulating a cooling medium within said casing throughout said drive means; and sealing means disposed between said support means and said casing for preventing leakage of said cooling medium from said casing.

5. A mining apparatus comprising: a main frame; disintegrating means mounted on said frame for cutting contiguous bores in advance of said frame; an elongated rotatable drum having cone-shaped casing located adjacent the opposite ends of said elongated drum, respectively; cutting elements secured to said drum and said rotatable casings providing a drum cutter and end cutters, respectively, said end cutters combining with said disintegrating means to provide a rib to roof contour; a drive housing enclosed within said drum; support means pivotally mounted on said frame for rotatably supporting said drum and saidcasings; said support means lying completely Within the outline of such rib to roof contour; means flexibly connecting said drive housing to said support means for locking said housing against torsion; drive means enclosed within said drive housing for rotating said drum and effecting rotation of said casings; said drive means comprising at least one motor secured to said housing and a gear reduction mechanism operatively connecting said motor to said drum and said end cutters.

6. A mining apparatus comprising a main frame; disintegrating means mounted on said frame for cutting contiguous bores in advance of said frame; an elongated rotatable drum having cone-shaped casings located adjacent the opposite ends of said elongated drum, respectively; cutting elements secured to said drum and said cone-shaped casings providing a drum cutter and cone cutters, respectively, said cone cutters combining with said distintegrating means to provide a rib to roof contour; a drive housing enclosed within said drum; support means pivotally mounted on said frame for rotatably supporting said drum and said cone-shaped casings said support means lying completely within the outline of such rib to roof contour; means flexibly connecting said drive housing to said support means for locking said housing against torsion; drive means enclosed within said drive housing for rotating said drum and effecting rotation of said cone-shaped casings; said drive means comprising at least one motor secured to said housing and having a rotatable shaft, a multi-stage gear reduction mechanism operatively connected to said shaft, and means flexibly connected to said gear reduction mechanism for transmitting torsion from said gear reduction mechanism to said rotatable drum; means secured to said rotatable shaft for circulating a cooling medium within said drum and throughout said drive means; and sealing means disposed between said support means and said drum for preventing leakage of said cooling medium from said drum.

7. A mining apparatus as defined in claim 6 in which said casings are journaled for rotation about axes which diverge from a vertical plane cut along the center of said drum transversely to the longitudinal axis of said drum.

8. A mining apparatus as defined in claim 7 in which said axes are disposed downwardly with respect to a horizontal plane cut along the longitudinal axis of said drum.

9. A mining apparatus comprising: a main frame; disintegrating means mounted on said frame for cutting contiguous bores in advance of said frame; a rotatable roof cutter drum transversely disposed relative to said bores, said drum having cutting elements thereon; drive means for rotating said cutter drum; support means connected to said frame rearwardly of said disintegrating means for rotatably supporting said cutter drum; and means for pivoting said support means about at least one horizontal axis into different elevated positions relative to said bores including an uppermost position in which a portion of said cutter drum is disposed a substantial distance above the peripheral orbit of said bores and the support means lies within the periphery of the contiguous bores formed by the disintegrating means in all elevated positions of said support means.

10. A mining apparatus comprising: a main frame; disintegrating means mounted on said frame for cutting contiguous bores in advance of said frame; a rotatable roof cutter drum transversely disposed relative to said bores, said drum having cutting elements thereon; drive means enclosed within said drum for rotating said cutter drum; support means connected to said frame rearwardly of said disintegrating means for rotatably supporting said cutter drum; and means for pivoting said support means about at least one horizontal axis into different elevated positions relative to said bores including an uppermost position in which a portion of the cutter drum is disposed a substantial distance above the peripheral orbit of said bores and the support means lies within the periphery of the contiguous bores formed by the disintegrating means in all elevated positions of said support means.

11. A mining apparatus comprising: a main frame; disintegrating means mounted on said frame for cutting contiguous bores in advance of said frame; a rotatable roof cutter drum transversely disposed relative to said bores, said drum having cutting elements thereon; electrically powered drive means enclosed within said drum for rotating said cutter drum; support means connected to said frame rearwardly of said disintegrating means for rotatably supporting said cutter drum; electrical connect tions extending through said support means from said frame to said drive means; means for circulating a cooling medium within said drum and throughout said drive means; sealing means disposed between said support means and said drum for preventing leakage of said cooling medium from said drum; and means for pivoting said support means about at least one horizontal axis into different elevated positions relative to said bores including an uppermost position in which a portion of the cutter drum is disposed a substantial distance above the peripheral orbit of said bores and the support means lies within the periphery of the contigous bores formed by the disintegrating means.

12. In a cutting machine:

a pair of spaced frame members;

a hollow cutter drum extending between said frame members and journaled on said frame members for rotation about the central axis of said drum, the outer surface of said drum having cutting bits extending radially outward therefrom; a pair of axially spaced internally toothed ring gears disposed within said drum; an electrical motor disposed within said drum having an outer field portion coaxial with said drum and having an inner a-rrnature portion rotatable about the central axis of said drum; wires secured to one of said frame members, effective to conduct current to field coils on the outer portion of said electric motor; additional electrical rigging adapted to conduct current from the outer field portion of said motor to the armature thereof; a first pinion gear connected to the armature portion of said motor; a double reduction gear train means cooperable with said ring gears to apply rotative force to said drum. 13. A mining apparatus comprising: a main frame; disintegrating means mounted on said frame for cutting contiguous bores of in advance of said frame; a pair of spaced frame members pivotally mounted on said main frame, said frame members lying within the periphery of said contiguous bores; a hollow cutter drum extending between said frame members and journaled on said frame members for rotation about the central axis of said drum, the outer surface of said drum having cutting bits extending radially outward therefrom; a pair of axially spaced internally toothed ring gears disposed within said drum; an electrical motor disposed within said drum and having an inner armature portion rotatable about the central axis of said drum; wires secured to one of said frame members, effective to conduct current to field coils on the outer portion of said electric motor; additional electrical elements adapted to conduct current from the outer field portion of said motor to the armature thereof; a first pinion gear connected to the armature portion of said motor; first and second planetary carriers having common axis of rotation coinciding with the axis of said drum; a first intermediate gear journaled on said first carrier for meshing engagement with said first pinion gear and one of said pair of ring gears, effective to rotate said first carrier about its axis of rotation while said first intermediate gear is revolving around said first pinion gear; a second pinion gear connected to said first carrier for rotation about said axis of rotation; and a second intermediate gear journaled on said second carrier for meshing engagement with said second pinion gear and the other of said pair of ring gears to apply rotative force to said second carrier and said drum.

References Cited UNITED STATES PATENTS 787,333 4/1905 Hughes et al -104 X 2,355,342 8/1944 Van Wormer 175-17 2,430,364 11/ 1947 Peale et a1. 299-78 X 2,762,141 9/ 1956 LeTourneau 299-6-5 X 2,803,445 8/1957 Borrowdale 175-104 X 2,878,000 3/1959 Felbeck 299-59 X 3,148,918 9/1964 Sibley 299-71 X 3,290,096 12/1966 Stalker 299-78 ERNEST R. PURSER, Primary Examiner. 

1. A MINING APPARATUS COMPRISING: AN ELONGATED ROTATABLE CASING HAVING CUTTING ELEMENTS THEREON; SUPPORT MEANS FOR ROTATABLY SUPPORTING SAID CASING; SEALING MEANS DISPOSED BETWEEN SAID CASING AND SAID SUPPORT MEANS FOR PREVENTING LEAKAGE THEREBETWEEN SO THAT SAID CASING IS A FLUID TIGHT HOUSING HAVING A LIQUID COOLING MEDIUM THEREIN; DRIVE MEANS ENCLOSED WITHIN SAID CASING FOR ROTATING SAID CASING; AND MEANS ENCLOSED IN SAID CASING FOR CIRCULATING SAID COOLING MEDIUM THROUGHOUT SAID CASING AND SAID DRIVE MEANS. 